
import java.util.Scanner;

public class math {


    public static void main(String[] args) {
        int count = 0;
        for(int i = 1;i<=100;i++)
        {
            if(i%10==9||i/10==9)
            {
                if(i%10==9&&i/10==9)
                {
                    count++;
                }
                count++;
            }
        }
        System.out.println(count);
    }



    public static void main3(String[] args) {

        for(int i =1000;i<=2000;i+=4)
        {
            if((i%4==0&&i%100!=0)||i%400==0)
            {
                System.out.print(i+" ");
            }
        }
    }





    public static void main2(String[] args) {
        for(int i = 2;i<=100;i++)
        {
            if(i==2||i==3||i==5||i==7)
            {
                System.out.print(i+" ");
            }
            if(i%2!=0 && i%3!=0 && i%5!=0 && i%7!=0)
            {
                System.out.print(i+" ");
            }
        }
    }




    public static void main1(String[] args) {

        Scanner sc = new Scanner(System.in);
        System.out.println("请输入一个整数：");
        int num = sc.nextInt();
        if(num==2||num==3||num==5||num==7)
        {
            System.out.println(num+"是个素数！");
        }
        else if(num>10 &&num%2!=0 && num%3!=0 && num%5!=0 && num%7!=0)
        {
            System.out.println(num+"是素数！");
        }
        else
        {
            System.out.println(num+"不是素数！");
        }
    }
}
